A service provider may provide a variety of computer-related services that are intended for use by individuals. Examples of computer-related services that may be intended for use by individuals include email services, personal web page services, personal data storage services, web access accounts, etc.
A service provider may be vulnerable to abuse by unscrupulous parties who misuse computer-related services that are intended for use by individuals. For example, an unscrupulous party may create numerous accounts with a free email service that is intended for individuals and then abuse the obtained email accounts for mass mailings of spam. Similarly, an unscrupulous party may create numerous free personal web page accounts that are intended for individuals and then abuse the web page accounts by storing large volumes of information on the obtained web storage space.
A service provider may attempt to prevent abuse of their services by screening applicants for their services. For example, a service provider may generate a registration web page that presents a human test that includes one or more test objects. The test objects may be used to determine whether an applicant for their services is a human being or a software program that mimics human behavior. For example, a test object may be an image of a stylized decimal number that is intended to test the human capability to recognize stylized numbers. A human being may pass the human test by providing an answer to one or more questions pertaining to the test objects.
Unfortunately, an abusive party may defeat a human test by capturing the test objects and presenting the test objects to an unsuspecting human being. For example, an abusive party may capture a test object from a registration web form and then re-create the human test in an entrance web page of a web site that has been created by the abusive party to be enticing to human beings, e.g. a pornographic web site. A human being seeking access to the enticing web site may provide a correct answer to the human test. The answer to the captured human test may then be used in an answer back at the registration web page of the service provider. In addition, an abusive party may employ low-paid laborers, e.g. individuals in developing countries, who are capable of repeatedly passing a human test to create numerous accounts with a service provider.